Process relating to the production of nickel carbonyl



Patented May 23, 1939 I UNITED. STATES PROCESS RELATING TO THE PRODUCTION OF NICKEL CABBONYL Albert Edward Wallis, Clydach, England, assignor to The International Nickel Company, Inc., New York, N. Y., a corporation of Delaware No Drawing. Application August 2a, 1937, Serial No. 161,420. In Great Britain September 9,

4 Claims.

The present invention relates to the production of nickel carbonyl.

It is well-known that in the Mond process of producing nickel carbonyl, a nickel matte is sub- 5 jected to the action of a reducing gas. The finely divided particles of metallic nickel contained in the reduced matte are extremely active and can be converted into nickel carbonyl by the action of carbon monoxide at atmospheric pressure, but the matte after reduction must be kept out 0! contact with air, otherwise the finely divided nickel and copper in the reduced matte are rapidly oxidized. If the carbonyl formation is to be carried on at atmospheric pressure, it is essential that the matte should be in finely-divided form and that it should have been reduced by means of a gas. This procedure is relatively expensive and somewhat troublesome. When finely powdered and gas-reduced matte isused in this manner, the reaction with compressed carbon monoxide is very vigorous and local overheating occurs due to heat generated in the reaction.

Various proposals have been made to form nickel carbonyl directly from an unreduced matte or from nickel compounds by causing caron an industrial scale for the production of a commercial product.

I have discovered an improved process which is eflicient and economical and which avoids the defects set forth hereinabove to a large extent by using as a raw material a sintered nickel matte which is reduced by heating with coal, coke, heavy oil, or other appropriate carbonaceous reducing agent. I I

It is an object of the present invention to provide an improved process for the production of nickel carbonyl in which nickel matte is reduced by solid or other appropriate carbonaceous reducing agent.

It is another object of the invention to provide an improved process of producing nickel carbonyl in which the nickel-containing material in a reduced condition is reacted in coarse, granular form directly with carbon monoxide to form nickel carbonyl.

A further object of the invention is to provide a process for the production 01' a reduced nickel matte which can be exposed to air. without oxidation'oi' the finely divided nickel and copper distributed in the reduced matte.

The invention also contemplates the provision of a process for producing nickel carbonyl in whichthenickel-containingmaterialinarebon monoxide to act on'the matte or compounds duced condition can be reacted with carbon monoxide at comparatively lowpressures to produce nickel carbonyl.

It is also within the contemplation of the invention to provide a process in which reduced nickel 5 matte can be reacted with compressed carbon monoxide to form nickel carbonyl without the occurrence of detrimental local overheating in the mass.

Other objects and advantages of the present invention will become apparent from the following description of a prefered embodiment of the invention.

Generally speaking the present invention con templates using sintered nickel matte as a raw material which is reduced by heating with coal, coke, heavy oil or other appropriate carbonaceous reducing agent. In this manner, amaterial is produced in a reduced condition which can be stored in the open air and which can be converted into nickel carbonyl, without preliminary fine grinding by treatment with carbon monoxide under a pressure which, although distinctly higher than atmospheric pressure, need not be nearly so high as those necessarily'used if nickel carbonyl is to be formed directly from unreduced matte. The reactionproceeds steadily to completion until substantially all of the nickel is extracted, with no tendency to local overheating.

The carbonaceous reducing agent may conveniently be charcoal, coke, bituminous or anthracite coal or the like, preferably in the form of a powder or dust. Instead of using a solid material, a heavy oil may be used, if desired. A particularly suitable carbonaceous material is an- 35 thracite coal of low ash content.

In carrying the invention into practice on an industrial scale, I have found that satisfactory results may be obtained by using a matte rich in nickel. For this reason, I prefer to use a matte that has been rendered rich in nickel sulphide by the Ori'ord tops and bottoms" process. In this-well known process, copper-nickel matte is fused with sodium sulphide and, when the melt is cooled, it separates into two layers, known as tops and bottoms." The tops" consist largely of copper-sodium sulphide and the bottoms mainly of nickel sulphide but containing some copper sulphide. By subjecting the bottom from the first treatment to a further smelting with soda flux, second bottoms are produced that are-richer in nickel sulphide than the first bottoms" and it is preferred to use "second bottoms? in the process of the present invention for this reason. When second bottoms from the Orford process are through a sintering machine the sulphides are converted into oxides with the evolution of an amount of heat suiiicient to sinter the resultant oxides. The resultant product generally has a chemical analysis ap- 00 proximating about 77% nickel, 2% copper, 0.5 to 0.6% iron, 0.4 to 0.6% cobalt and the balance oxygen. It has been found the sintered matte is preferably used in a coarse, granular form, for example about A inch in diameter. The carbonaceous reducing agent, if solid, may also be used in the same granular form, but it is preferably used in a finely divided state, becauseit is found that in this way the reduction takes place more rapidly at considerably lower temperatures. Further, coal or anthracite dust is a cheap and readily available material. After mixing the granular sintered matte with the carbonaceous reducing agent the mixture may be heated in a rotary kiln or other suitable furnace to a temperature above about 750 C. and preferably about 900 C., but never exceeding 1000 C., for aperiod of about 1 to '6 hours. The quantity of carbonaceous reducing agent may vary from about 10% to about of the weight' of the sintered matte, about 30% usually being found satisfactory.

After reduction the, matte, which generally undergoes further sintering during the reduction process, is cooled to about 200 C., and preferably to about 100 C., before exposure to the air. It may thereafter be stored in the open air without detriment to the subsequent nickel extraction process.

The sintered matte after reduction as described above may be directly introduced into the reaction chamber and treated with carbon monoxide, or if desired any excess of carbonaceous material which may be present may first be separated from the reduced matte and used again for the reduction of further sintered matte. 'Being highly magnetic, the reduced sintered matte may readily be removed from the excess carbonaceous material in a magnetic separator of any desired type. The carbonyl formation may conveniently be carried on under pressures of about 20 to about 50 atmospheres and at temperatures of about 70 to about C.

For the purpose of giving those skilled in the art a better understanding of the invention, the following illustrative examples will be given:

Example No. 1

About 1000 parts by weight of mesh sintered second bottoms were intimately mixed with about 30% of its weight of anthracite dust. The mixture was heated, in a tube furnace to about 900 C. for about 2 hours. During this reduction process carbon'monoxide and carbon dioxidegases were evolved. The reduced matte was then Example No. 2

About 1000 parts by weight of 10 mesh sintered second bottoms was mixed with about 20% of its weight of about 60 mesh anthracite, and the mixture heated to about 800 C. for about 4 hours.

When gas evolution had ceased, the-product was allowed to cool out of contact with air.

It was then exposed to air for two weeks. Atter this time the reduced matte was nickel extracted with flowing carbon monoxide at about 50 atmospheres pressure at a reaction temperature, whereby about 96% of the total nickel was extracted in about 20 hours.

The process described hereinabove has a number of advantages over processes hitherto in use. The raw material is one which is readily available and the relatively expensive gas reduction used hitherto is avoided and replaced by a cheaper process. The reduced material can be stored in air, thereby avoiding the necessity for using a gastight and relatively complicated conveying plant. The material produced in a reduced condition can be used forthwith for the production of nickel carbonyl without any further mechanical or chemical treatment, and in particular the necessity for fine grinding with attendant dust losses and difliculty in handling is avoided.

I claim:

1. A method of preparing a reduced product containing nickel suitable for the preparation of nickel carbonyl by treatment with carbon monoxide under pressures of about 20 to 50 atmospheres and at temperatures of about 70 C. to 120 0., said method comprising sintering nickel matte in the presence of oxygen to produce a coarse granular sintered product containing nickel oxide, mixing said coarse granular sintered product with about 10% to 100% by weight of solid carbonaceous reducing agent in finely divided form, and heating said mixture at a temperature within the range of about 750 C. to 1000 C. to reduce said nickel oxide whereby a granular sintered reduced product containing nickel is produced which is capable of storage in air without practical detriment to the subsequent extraction of the nickel by treatmentwith carbon monoxide under pressures of about 20 to 50 atmospheres and at temperatures of about 70 C. to 120 C.

2. A method of preparing a reduced product containing nickel suitable for the preparation of nickel carbonyl by treatment with carbon monoxide under pressures of about 20 to 50 atmospheres and at temperatures of about 70 C. to 120 0., said method comprising sinteringnickel matte in the presence of oxygen to produce a coarse granular sintered product containing nickel oxide, mixing said coarse granular sintered product with a reducing agent selected from the group consisting of solid and liquid carbonaceous reducing agents, and heating said mixture to reduce said nickel oxide whereby a granular sintered reduced product containing nickel is produced which is capable of storage in air without practical detriment to the subsequent extraction of the nickel by treatment with carbon monoxide under pressures of about 20 to 50 atmospheres and at temperatures of about 70 C. to 120 C.

3. A method as set forth in claim 2 in which the nickel matte is Orford "second bottoms.

4. A method of preparing a reduced product containing nickel suitable for the preparation of nickel carbonyl by treatment with carbon monoxide comprising sintering nickel matte in the presence of oxygen to produce a coarse granular sintered product containing nickel oxide, heating said coarse granular sintered product with a carbonaceous reducing agent to redvce said nickel oxide wherebyagranular sintered reduced product containing nickel is produced which is suitable for the preparation of nickel carbonyl by treatment with carbon monoxide.

ALBERT EDWARD WALLIS. 

